The benefits of antimicrobial films is well established in certain fields, such as the health care industry and the food processing industry. The application of germicidal or sanitizing polymeric films having limited water solubility to a hard porous or nonporous surface often provides the necessary protection from contamination by any number of environmental bacterial or viral elements.
However, while the state of antibacterial films has evolved, there is limited versatility and variability in the films currently available for use. For instance, U.S. Pat. No. 2,984,639 to Stamberger et al provides for a cast polymeric antimicrobial film formed in situ from a two film-forming solutions having no one-part intermediate aqueous film-forming compositional phase.
While precipitate germicidal films such as that disclosed in Stamberger have been developed, the versatility of these films due to their limited solubility has been well documented. For example, U.S. Pat. No. 2,931,753 to Chesbrow provides an inorganic ammonium salt of a polysaccharide carboxylic acid having a limited solubility even in organic solvents. The Chesbrow composition, in fact, is soluble only to about 1% and then only in methanol. However, even a film-forming composition based in an organic solvent presents certain limitations to the health care and food processing industries due to the inherent toxicity and flammability of many organic solvents.
Some progress has been made in providing antimicrobial films from an aqueous carrier, as seen by U.S. Pat. No. 4,783,340 to McDonell et al. However, to avoid premature precipitation the McDonnell et al composition requires that the anionic polymer and quaternary constituents be stored separately and, further, applied only through a dual-head spray unit.